Mask for analyzed mammals

ABSTRACT

An encapsulatable life support mechanism (ELSM) for an analyzed animal, including: a cradle or bed adapted by means of size and shape to accommodate the animal; an anesthetization gas mask (AGM) characterized by a cup with conic cross section, comprising a plurality of apertures located at the outer circumference of the cup; a fluid supplying mechanism (FSM) in which the AGM is placed, the FSM is in a continuous fluid communication with (i) an anesthetization gas inlet positioned outside the ELSM and an outlet located within the ELSM; (ii) an air suction scavenging device positioned outside the ELSM and a mask and an air suction outlet located within the ELSM; and a plurality of (iii) air conditioning tubes; and an airtight shell enveloping the same. The airtight ELSM prevent leakage of anesthetization gas.

FIELD OF THE INVENTION

The present invention generally pertains to masks for behavior ofmammals, such as anesthetized mice and rats, scanned within an MRIdevice. The invention also relates to methods of treating mammals duringthe study thereof and to methods for reducing exposure of laboratorypersonnel to hazardous fluids.

BACKGROUND

MRI-compatible anesthesia gas masks for animals and MRI-compatibleplatforms for animal surgery are commercially available items; see forexample products of Stoelting Co (US), 2Biological Instruments (IT) etc.As designed by their producers, these gas anesthesia platforms andmouse, rat, dog etc. masks provide easy positioning of an animal duringanesthesia and surgery and often allow for anesthetization andpositioning of the animal outside of a stereotaxic device and for dorsalsurgery. The animal's teeth are usually placed over an incisor bar andthe mask slid forward until the cone fits snugly around the animal'snose, so that no nose clamp is required. The platform is then liftedonto an appropriate stereotaxic device, providing positioning of theanimal. The head of the animal is not perfectly conical, however. Eyes,ears and other organs of the animal do not perfectly fit the conicalmask, and hazardous leakage of anesthetization gas often occurs withinthe close environment of the laboratory. Cases in which laboratorypersonnel collapsed after breathing anesthetization gas applied toexperimental animals have been reported in the literature.

US patent application 2004/0216737 discloses an anesthesia system foradministering an anesthetic gas to the nose of an animal. The anesthesiasystem comprises a mask having a receptacle adapted to surround and forma fluid path to the animal's nose; a breather enclosure forming an airexchange chamber, the breather enclosure comprising a connectorconfigured for coupling with the mask to connect the receptacle and airexchange chamber in fluid communication; an inlet hub extending insidethe air exchange chamber and forming an inlet port through a wall in thebreather enclosure, the inlet port being adapted to convey theanesthetic gas into the chamber and to the mask; and a check valveconnected with the inlet hub and extending within the air exchangechamber, the check valve being operable in response to relative pressurein the air exchange chamber between an open position, which permitsanesthetic gas to enter the air exchange chamber, and a closed position,which substantially prevents anesthetic gas from entering the airexchange chamber, wherein the check valve moves to the open position inresponse to vacuum pressure created when the animal inhales, the checkvalve being normally biased in the closed position.

U.S. Pat. No. 6,363,931 discloses an occluder for supporting andpreventing escape of anesthesia gases through face masks when not inuse, comprising: a C-shaped support base with a flat base plate adaptedto fit beneath a surgical mattress, a side plate located in a planenormal to that of the base plate having a bottom edge contiguous withthe base plate and having a height equal to the thickness of a standardsurgical mattress, and a top plate contiguous with an upper edge of theside plate, the top plate being in a plane parallel to that of the baseplate; and a solid cylindrical support shaft supported on and extendingupwardly from the top plate, the cylindrical support shaft having a mainbody portion approximately 15 mm in diameter.

U.S. Pat. No. 4,633,890 discloses an apparatus for preventing theundesirable egress of anesthetic gas into ambient atmosphere, comprisinga tube having one end connected to an anesthesia machine and its secondend being a free end; the anesthesia machine supplying anesthetic gas tothe tube; the free end being removably connectable to a breathingpassage of a patient; an obturator post connected to the anesthesiamachine and constructed to sealingly engage the free end, for preventingthe undesirable egress of the anesthetic gas into the atmosphere of anoperating theater when the free end is disconnected from the breathingpassage; and a bore passing through the obturator post and communicatingwith exhaust means.

None of the above provides a simple solution for anesthetization andprecise positioning of the animal within an MRI device. Hence anMRI-compatible and safe mask would fulfill a long felt need.

BRIEF SUMMARY

It is thus one object of the invention to disclose an anesthetizationgas mask (AGM) characterized by a cup with conic cross section,comprising a plurality of apertures located at the outer circumferenceof the cup.

Another object of the invention is to disclose the AGM as defined above,wherein the mask is made of MRI-compatible materials.

Another object of the invention is to disclosed the AGM as definedabove, wherein the MRI-compatible materials are polymers.

Another object of the invention is to disclose the AGM as defined above,wherein the mask is adapted by means of size and shape, to ensureanesthetization of animals.

Another object of the invention is to disclosed the AGM as definedabove, wherein said animals are laboratory animals.

Another object of the invention is to disclose an anesthetization systemcomprising an AGM as defined above, a fluid supplying mechanism (FSM)accommodating the same, wherein the FSM is in continuous fluidcommunication with the anesthetization gas inlet and outlet, and an airsuction outlet.

Another object of the invention is to disclose an anesthetization systemcomprising an AGM as defined above, wherein the system further comprisesa mask maneuvering mechanism comprising an adjustment knob in connectionwith the mask, the knob is adapted to ensure that the mask remains in apredefined location within a housing of the FSM.

Another object of the invention is to disclose an encapsulatable lifesupport mechanism (ELSM) for an analyzed animal. The ELSM comprises acradle or bed adapted by means of size and shape to accommodate theanimal; an anesthetization gas mask (AGM) characterized by a cup with asubstantially conical cross section, comprising a plurality of apertureslocated at the outer circumference of the cup; a fluid supplyingmechanism (FSM) in which the AGM is placed, the FSM is in a continuousfluid communication with (i) an anesthetization gas inlet positionedoutside the ELSM and an outlet located within the ELSM; (ii) an airsuction scavenging device positioned outside the ELSM and a mask and anair suction outlet located within the ELSM; and optionally (iii) aplurality of air conditioning tubes; and an airtight shell envelopingthe same. The airtight ELSM prevents leakage of anesthetization gas fromthe ELSM outwardly to the laboratory; provides thermal isolation betweenambient air and the air-conditioned animal environment; and preventsaccidental spillage of hazardous materials such as, e.g., radioactiveagents, outside the environment in which the animal is accommodated.

Another object of the invention is to disclose an MRI-compatible ELSMand an ELSM wherein the AGN, FSM and mechanisms thereof are adapted bymeans of size and shape, to ensure anesthetization of animals.

Another object of the invention is to disclose and MRI-compatible ELSM,and an ELSM wherein the AGN, FSM and mechanisms thereof are adapted bymeans of size and shape, to ensure anesthetization of animals, whereinsaid animals are laboratory animals.

Another object of the invention is to disclose a mouse handling system(MHS) comprising an encapsulatable life support mechanism (ELSM) for ananalyzed animal; the MHS is a maneuverable elongated device,characterized by a proximal portion, held outside the MRI device, andcomprises at least one inner shaft and at least one outer shaft, the atleast one outer shaft telescopically maneuverable along the at least oneinner shaft to provide a telescopic mechanism of variable (proximal-)length; the MHS is further characterized by a distal portion comprisingthe ELSM, wherein the distal ELSM is rotatable and/or linearlyreciprocatable along the main longitudinal axis of the shafts by meansof the maneuverable telescopic mechanism of the proximal portion.

Another object of the invention is to disclose an MRI-compatible MHS andan MHS wherein the AGN, FSM and mechanisms thereof are adapted by meansof size and shape, to ensure anesthetization of animals.

Another object of the invention is to disclose an MRI-compatible MHS andan MHS wherein the AGN, FSM and mechanisms thereof are adapted by meansof size and shape, to ensure anesthetization of animals, wherein saidanimals are laboratory animals.

Another object of the invention is to disclose an MRI-compatible ELSMand an ELSM wherein the AGN, FSM and mechanisms thereof are adapted bymeans of size and shape, to ensure anesthetization of animals.

Another object of the invention is to disclose an MRI-compatible ELSMand an ELSM wherein the AGN, FSM and mechanisms thereof are adapted bymeans of size and shape, to ensure anesthetization of animals, whereinsaid animals are laboratory animals.

Another object of the invention is to disclose a safe method for formingan airtight capsule to prevent leakage of anesthetization gas from thegas supply inlets to the laboratory; and/or to prevent accidentalspillage of hazardous materials, e.g. radioactive agents, outside of theenvironment enclosing the animals; the method comprising steps ofproviding a mouse handling system (MHS) which is a maneuverableelongated device comprising an encapsulatable life support mechanism(ELSM) for the analyzed animal; characterizing the same by a proximalportion, held outside the MRI device, comprising at least one innershaft and at least one outer shaft, the at least one outer shafttelescopically maneuverable along the at least one inner shaft toprovide a telescopic mechanism of variable (proximal-) length; andfurther characterizing the same by a distal portion comprising the ELSM.The distal ELSM is rotatable and/or linearly reciprocatable along themain longitudinal axis of the shafts by means of the maneuverabletelescopic mechanism of the proximal portion.

Another object of the invention is to disclose a safe method forpreventing leakage of anesthetization gas from the gas supply inlets tothe laboratory. The method comprises steps of providing ananesthetization gas mask (AGM); further characterizing the same by a cupwith substantially conical cross section; and providing plurality ofapertures located at the outer circumference of the cup.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an MRD device including at least one port for use insertingtherein a Mouse Handling System (MHS), in accordance with a preferredembodiment of the present invention;

FIG. 2 shows the MHS including sealing flanges and a mouse holdingportion, in accordance with a preferred embodiment of the presentinvention;

FIG. 3 shows the details of the proximal portion of the MHS, inaccordance with a preferred embodiment of the present invention;

FIG. 4 shows the location of the mouse within the MHS, in accordancewith a preferred embodiment of the present invention;

FIG. 5 shows the details of the distal portion of the MHS, in accordancewith a preferred embodiment of the present invention;

FIGS. 6 a and 6 b show the flushing air device, in accordance with apreferred embodiment of the present invention, and

FIG. 7 shows a conic mask 32, in accordance with a preferred embodimentof the present invention.

DETAILED DESCRIPTION

The following description is provided in order to enable any personskilled in the art to make use of the invention and sets forth the bestmodes contemplated by the inventor of carrying out this invention.Various modifications, however, will remain apparent to those skilled inthe art, since the generic principles of the present invention have beendefined specifically to provide a mask for analyzed mammals and methodsusing the same.

The term ‘Magnetic Resonance Device’ (MRD) specifically applieshereinafter to any Magnetic Resonance Imaging (MRI) device, any NuclearMagnetic Resonance (NMR) spectroscope, any Electron Spin Resonance (ESR)spectroscope, any Nuclear Quadruple Resonance (NQR) spectroscope or anycombination thereof. The MRD hereby disclosed is optionally a portableMRI device, such as the ASPECT Magnet Technologies Ltd commerciallyavailable devices, or a commercially available non-portable device.Moreover, the term ‘MRD’ generally refers in this patent to any medicaldevice, at least temporary accommodating an anesthetized animal.

The term ‘about’ refers herein to a value of ±25% of the definedmeasure.

Reference is now made to FIG. 1, schematically illustrating, not toscale, an MRI device, such as an MRD 10, comprising at least one port110. A mouse handling system (MHS, 100), which is a maneuverableelongated device, is inserted through the port 10. In preferredembodiments, the MHS 100 is characterized by a substantially circularcross-section and a proximal portion 20, which is located outside theMRD 10. The MHS 100 further includes a a shaft 21, and a distal portion30(see FIG. 2). The maneuverable MHS 100 is rotatable about longitudinalaxis of the shaft 21 (FIGS. 1 and 2) and is translationally maneuverableparallel to the shaft 21. The proximal end 20 is slideable over theshaft 21, providing a telescopic mechanism of variable length.

Reference is now made to FIG. 2, schematically illustrating, not toscale, the MHS 100 includes the flange 11 a and a flange 11 b, locatedat a distal opposite end of the MHS 100. The MHS 100 is inserted intoport 110 of the MRD 10. The proximal portion 20 of MHS 100 comprises aplurality of levers and handles (22 a and 22 b) which lock the locationof the maneuverable MHS 100, within the MRD 10 and a connectionmechanism adapted to communicate the encapsulated environment of thedistal portion 30 with the proximal portion 20, by means of a pluralityof fluid-connecting pipes (not shown here). The proximal end 20 of MHS100 comprises a plurality of indicia, such as a rotation indication 23b, positioned on the shaft 21 indicates the angular and translationalrelative position of the MHS 100 with respect to MRD 10. According toone embodiment of the invention, the proximal portion 20 of the MHS 100includes an airtight capsule 30 comprising a shell 22, an animal bed orcradle 31, for locating an animal 1 to be studied as well as a fluidsupplying mechanism 33. The role of shell 22, inter alia, is (i) to forman airtight capsule to prevent leakage of anesthetization gas from thegas supply inlets to the laboratory environment; (ii) to provide thermalisolation between the laboratory environment the air-conditionedenvironment surrounding the animal in the shell 22 and the laboratoryenvironment; and (iii) to prevent accidental spillage of hazardousmaterials, e.g. radioactive agents outside the shell 22 surrounding theanimal.

Reference is now made to FIG. 3, schematically illustrating, not toscale, the proximal portion 20 of MHS 100, which comprises the shaft 21upon which a translational scale 22 a and a rotation scale 23 b arepositioned, and a distal portion 30 (here without shell 20), where mouse1 is lying thereon the cradle 31.

Reference is now made to FIG. 4, schematically illustrating, not toscale, the distal portion 30. The mouse 1 is immobilized on the cradle31 and its head is placed within a mask 32. The position of the mask 32within a housing 33 is determined by means of rotatable rod 34.

Reference is now made to FIG. 5, schematically illustrating, not toscale, the distal portion 30. According to one embodiment of theinvention, the cradle 31 comprises a heating/cooling mechanism 38. Mask32 may comprise mouthpiece 35 and anesthetization gas outlet 35 a influid communication with anesthetization gas inlet 35 b. Mask 32 islocated within a housing of fluid supply mechanism 33, and its positionis accurately determined by rod 34.

Anesthetization gas is supplied to the animal via outlet 35 a with flowf (cm³/sec). Air suction is provided from the mask 32 and aperturesthereon (not shown) via inner portion of the housing 33 to suctionoutlet 37 with flow F, wherein F>>f. Hence, leakage of anesthetizationgas from outlet 35 a and the inner portion of capsule 22 to the externalenvironment of the laboratory is avoided.

Reference is now made to FIGS. 6 a and 6 b, schematically illustrating,not to scale, the facilitated flow of flushing air device. The flowbegins from the behind anesthetization gas inlet 35 b and passes aroundthe animal's head via mask 32 and plurality of apertures 32 a into theBernoulli-type orifice 32 b (orifice 32 b is narrow relative to thewidest diameter of the mask), via a hollow chamber 33 a of the housing33, to an outlet 37 and to a gas scavenger located outside the MRD.

Reference is finally made to FIG. 7, schematically illustrating, not toscale, a conic mask 32 and its plurality of apertures 32 a, aBernoulli-type orifice 32 b (orifice 32 b is narrow relative to thewidest diameter of mask), and adapter 32 c which couples the mask 32 tothe housing 33 in a maneuverable manner. The role of apertures 32 alocated in the outer circumference of the mask is to ensure effectiveflushing of air due to the irregular geometry of the animal's head 1,and to avoid blocking of air suction by the animal's body parts and fur.

Examples of various features/aspects/components/operations have beenprovided to facilitate understanding of the disclosed embodiments of thepresent invention. In addition, various preferences have been discussedto facilitate understanding of the disclosed embodiments of the presentinvention. It is to be understood that all examples and preferencesdisclosed herein are intended to be non-limiting.

Although selected embodiments of the present invention have been shownand described individually, it is to be understood that at least aspectsof the described embodiments may be combined.

Although selected embodiments of the present invention have been shownand described, it is to be understood the present invention is notlimited to the described embodiments. Instead, it is to be appreciatedthat changes may be made to these embodiments without departing from theprinciples and spirit of the invention, the scope of which is defined bythe claims and the equivalents thereof.

What is claimed is:
 1. A safe method for forming an airtight capsule toprevent leakage of anesthetization gas from the gas supply inlets to thelaboratory; and/or avoiding accidental spillage of hazardous materials,outside mice environment; said method comprising steps of: a. providinga mouse handling system (MHS) comprising an encapsulatable life supportmechanism (ELSM) for said analyzed animal; b. providing said MHS is anmaneuverable elongated device; c. characterizing the same by a proximalportion, held outside the MRD, comprises at least one inner shaft and atleast one outer shaft, said at least one outer shaft telescopicallymaneuverable along said at least one inner shaft to provide a telescopicmechanism of variable (proximal-) length; and d. further characterizingthe same by a distal portion comprising said ELSM, wherein said distalELSM is rotatable and/or linearly reciprocatable along the mainlongitudinal axis of said shafts by means of said maneuverabletelescopic mechanism of the proximal portion.
 2. The safe methodaccording to claim 1 wherein said hazardous materials compriseradioactive agents.